1. Technical Field
The present disclosure relates to a mixed electrode material for a nonaqueous electrolyte battery, and more particularly to a negative electrode material for a lithium ion battery and a lithium ion battery.
2. Related Art
Nonaqueous electrolyte batteries have been put into practical use as batteries for vehicles including hybrid vehicles and electric vehicles. As such nonaqueous electrolyte batteries for the on-vehicle power source, lithium ion secondary batteries have been desired to have higher energy density, excellent input and output characteristics, and longer life. For improving the acceleration performance at the start of a vehicle, in particular, it is important to increase the output of the lithium ion secondary battery.
Carbon materials are used as the negative electrode material for a lithium ion battery. For improving the output characteristic of the lithium ion battery, the material obtained by mixing graphite and amorphous carbon at a predetermined ratio is used (JP-A-2011-54371). According to JP-A-2011-54371, the lower output at the end stage of the discharge can be suppressed because the graphite material can maintain higher battery voltage than the amorphous carbon material, and thereby, the battery can have a higher output characteristic by the use of the material obtained by mixing the graphite material and the amorphous carbon material. JP-A-2011-54371 discloses examples of the graphite material and the amorphous carbon material with the characteristics applicable to the mixed negative electrode material.